fix(q-w0): six audit fix-nows — linked-lag stereo SOLA, playable-span prime bound, declick dead-state, provenance cursor hardening, rate-derived gain ramp + fade ceiling

src/vst/reasampler_editor.h

@@ -318,6 +318,11 @@ private:
     // into the control's stored domain) or a toggle's `segment` (0/1). Mutates `play` in place.
     void applyControl(int id, ZonePlaySeconds& play, double value, int segment) const;
 
+    // The Trigger fade-in/out knob full-scale, in SOURCE frames: kFadeMaxSeconds (2 s
+    // wall-clock) resolved against the live rate at use (Q-W0 T3-03 — never a baked-in
+    // rate). 44.1 kHz fallback before setupProcessing has run. Storage stays frames.
+    double fadeMaxFrames() const;
+
     // --- S-VIEW-3 envelope overlay seam (frames <-> fraction converter) ----------
     //
     // envelope_overlay's AmpEnvelope is a DERIVED VIEW, not a TriggerParams copy: it stores the